Morphological And Molecular Identification Of Beauveria And Its Pathogenicity In Locusta Migratoria Manilensis

The majority species of Beauveria genus are important entomogenous fungi, and play an important role in pest biocontrol.In this study, we isolated several Beauveria strains from wild-collected samples, and identified all the strains through the morphology and molecular biology methods, and determined the pathogenicity of part of them in Locusta migratoria manilemis.(1) To avoid bacterial contamination during separation, we selected the isolation medium of anti-bacterial contamination (PDA+Penicillin+Streptomycin), and gained the appropriate PDA medium which supplemented with the antibiotic concentration of100IU/mL. After separation from15wild-collected samples, we got8Beauveria strains, according to the morphological analysis and ITS sequence analysis, they were identified as Beauveria bassiana, According to the morphological observation, the measure of conidiophores and conidia for all Beauveria strains, we found that it is not easy to distinguished between B. brongniartii, B. amorpha and B. caledonica, because of the similar morphology; B. velata and B. aranearum as well.(2) We used the ITS sequences and β-tubulin sequence of the strains tested, but they can not fully distinguish between the various strains. Neighbor-joining tree which build by three software generated from the ITS region sequence and β-tubulin sequence of Beauveria, the tree structure was broadly similar, and the different strains of B. bassiana were spread out in different branches, but other kinds of strains were scattered in the B. bassiana in different branches. The branch parts of different trees were always consistent.(3) We selected15strains of B. bassiana, used three ways which were triangle bottle colony feeding method, worm dipping method and leaf dipping method to infect larvae of3rd L. migratoria manilensis. The result shown that colony feeding method was the fastest than other methods, the result also received Bb03strain that lethal speed was the fastest. We used different concentrations of the Bb03strains spore suspension to infect larvae of3rd L. migratoria manilensis, the result shown that optimal spore concentration was1.54×107spores/mL.In this research, the species of Beauveria were classification and determination by morphology and molecular level, which provided theory basis for identification of Beauveria strains. The strong pathogenic strain laid the foundation for the study of biological control to L. migratoria manilensis.